In a battery system, a charging/discharging management unit controls charging and discharging of a secondary battery such as a lithium ion secondary battery through a battery control unit (BMU: Battery Management Unit).
If an abnormality occurs during the operation of the battery control unit of the battery system, a constituent element in which the abnormality has occurred is reset. For example, Patent Literature 1 discloses a technique that resets a communication unit that communicates with a device if the communication state with the device is lost. In addition, Patent Literature 1 discloses another technique that cumulates the charged/discharged current of the secondary battery while it is normally operated and calculates the remaining capacity of the secondary battery based on the cumulative capacity.